Apparatus and method for stabilizing an earthen embankment

ABSTRACT

A structure for stabilizing an earthen embankment comprises an embankment support for restraining movement of at least a part of the embankment, a flexible fiber geogrid ( 5 ) extending longitudinally through the embankment from a first end portion secured to the support to a second end portion, and anchor means ( 55, 60, 11 ) for securing one of the end portions. The anchor means comprises a pair of anchor rods ( 55, 60 ) extending transversely in relation to the geogrid, and means ( 11 ) for limiting movement of the anchor rods. The end portion secured by the anchor means is wrapped back and forth around the anchor rods so as to tighten thereon when the geogrid is pulled in longitudinal tension away from the anchor means. A method of anchoring a flexible fiber geogrid to a support utilizing such anchor rods is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. provisional application No.60/449,392 filed Feb. 25, 2003, entitled “APPARATUS AND METHOD FORSTABILIZING AN EARTHEN EMBANKMENT”, naming Michael Charles Kallen as theinventor. The contents of the provisional application are incorporatedherein by reference in their entirety, and the benefit of the filingdate of the provisional application is hereby claimed for all purposesthat are legally served by such claim for the benefit of the filingdate.

BACKGROUND OF THE INVENTION

The present invention relates to apparatus and methods for stabilizingearthen retaining walls or embankments.

It is well known in the prior art to stabilize earthen embankments withsupports and associated geogrids extending rearwardly from the supportinto the stabilized embankment. This includes embankments with a slopeof less than 90 degrees and embankments with a 90 degree slope. In caseswhere flexible fiber geogrids are used, the geogrid often is wrappedover the face of the support and under the floor of the support But, thetime and labor required to instal such geogrids is substantial.

Flexible fiber geogrids are available from various sources, for example,Strata Systems, Inc. of Cumming, Ga., U.S. who provide a family of highstrength polyester yarn geogrids for soil reinforcement.

U.S. Pat. No. 5,975,810 (Taylor et al.) granted on Nov. 2, 1999discloses apparatus for securing a flexible fiber geogrid to a supportwithout wrapping over the face of the support. In a number ofembodiments there is a need to carefully fold the forward end portion ofthe geogrid back and forth in layers upon itself to provided improvedshear strength. The layered end portion is then secured with a retainingrod which is positioned to press against the layers—in effectsandwiching the layers between the rod and the underlying support onwhich the layers are positioned. In the field, the required alignedfolds may be considered awkward and time consuming to achieve. Further,the anchorage does not have a positive hold on the geogrid. Theintegrity of the anchorage when the geogrid is tensioned appears to belargely dependent upon the compressive grip which the retaining rodimposes on the folded layers. In another embodiment, Taylor et al.describe anchoring a geogrid by means of a retaining rod around whichthe forward end of a geogrid is folded 180 degrees backwards. However,by itself, the rod does not provide a positive hold on the geogrid. Thegeogrid is restrained only by the resistance of backfill which isrequired to be placed over the folded end portion of the geogrid beforetension is applied to the geogrid. The sufficiency of the restraint willbe dependent on the length of the folded end portion and frictionalcharacteristics of the backfill, the latter of which may vary dependingon dampness and other factors. To adjust for such considerations willrequire particular skill and expertise on the part of those determiningwhat length a folded portion should have to achieve a desired connectionstrength.

Accordingly, there is a need to provide apparatus and a method forpositively anchoring a flexible fiber geogrid to a support with astrong, reliable connection which requires minimal labor.

BRIEF SUMMARY OF THE INVENTION

In a broad aspect of the present invention, there is provided astructure for stabilizing an earthen embankment which comprises anembankment support for restraining movement of at least a part of theembankment, a flexible fiber geogrid extending longitudinally throughthe embankment from a first end portion secured to the support to asecond end portion, and anchor means for securing one of the endportions. The anchor means comprises a pair of anchor rods extendingtransversely in relation to the geogrid, and means for limiting movementof the anchor rods. The end portion secured by the anchor means iswrapped back and forth around the anchor rods so as to tighten thereonwhen the geogrid is pulled in longitudinal tension away from the anchormeans.

In one embodiment, the embankment support comprises a retaining wall andthe means for limiting movement of the anchor rods comprises a pluralityof anchor bolts, each bolt comprising a shaft extending from one endengaged with the wall to a distal end shaped to form an eyelet, one ofthe anchor rods extending through each of the eyelets.

In another embodiment where the embankment support also comprises aretaining wall, the earthen embankment lies between a rock face and thewall. The means for limiting movement of the anchor rods comprises aplurality of anchor bolts, each bolt comprising a shaft extending fromone end engaged with the rock face to a distal end shaped to form aneyelet, one of the anchor rods extending through each of the eyelets.

In a further embodiment, the embankment support of the stabilizingstructure comprises a floor section and a face section. The floorsection extends longitudinally rearwardly from a forward end of thefloor section to a rearward end and includes at the rearward end aplurality of transversely spaced hooking members. The face sectionextends upwardly from the forward end of the floor section to a top endof the face section at an angle corresponding to the slope of theembankment (i.e. up to 90 degrees). The geogrid extends longitudinallyrearwardly from the floor section and is anchored thereto by first andsecond anchor rods extending transverse to the geogrid. Movement of theanchor rods relative to the support is limited by the hooking memberswhen the geogrid is pulled in rearward longitudinal tension. At least insome circumstances, each hooking member preferably defines an invertedU-shaped envelope. In such cases, the geogrid preferably extends from aforward end of the geogrid:

-   -   first forwardly above the first anchor rod, preferably a        cylindrical rod, to a position above the second anchor rod, also        preferably a cylindrical rod;    -   then wrappingly around the second anchor rod to a position below        the second anchor rod;    -   then rearwardly to a position above the first anchor rod;    -   then wrappingly around the first anchor rod to a position below        the first anchor rod;    -   then forwardly to a position below the second anchor rod;    -   then wrappingly around the second anchor rod to a position above        the second anchor rod;    -   then rearwardly above the first anchor rod and away from the        support

In another aspect of the present invention, there is provided a methodof anchoring a flexible fiber geogrid to a support for stabilizing anearthen embankment, the support comprising an upwardly extending facesection and a floor section extending longitudinally rearwardly from theface section. The floor section comprises a plurality of transverselyspaced hooking members, and the geogrid comprises longitudinallyextending webs sized and spaced to fit between the hooking members. Themethod comprises:

-   -   positioning a forward end portion of the geogrid atop the floor        section such that the longitudinally extending webs of the        geogrid extend between the hooking members;    -   then positioning a first anchor rod atop the end portion of the        geogrid rearward of the hooking members in a position where        forward movement of the first anchor rod is limited by the        hooking members;    -   then folding the end portion of the geogrid forwardly over the        first anchor rod;    -   then positioning a second anchor rod atop the end portion of the        geogrid forward of the first anchor rod in a position where        rearward movement of the second anchor rod is limited by the        hooking members;    -   then folding the end portion and the geogrid rearwardly over the        second anchor rod.

The foregoing structure and method enables a flexible fiber geogrid tobe anchored to a support in a quick and efficient manner withoutimposing undesirable stresses on the geogrid when the geogrid istensioned in relation to the support. Another key point to note is thatunlike the systems of Taylor et al. the strength of the anchoringconnection (viz. the “pull-out” factor) will proportionately increase asthe longitudinal tension applied to the geogrid is increased. Further,since the anchoring connection of the present invention is not dependenton placing backfill on the connection to provide resistance, theconnection is necessarily independent of the quality of backfill thatultimately is added. The frictional resistance which backfill may haveto offer is immaterial to the connection strength.

The foregoing and other features and advantages of the present inventionwill now be described with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representational cross-section elevation view of a verticalearthen embankment stabilized by apparatus in accordance with thepresent invention.

FIG. 2 is a representational cross-section elevation view of a slopedearthen embankment stabilized by apparatus in accordance with thepresent invention.

FIG. 3 is a perspective view illustrating in more detail the linking ofthe supports shown in FIG. 1. Similar linking is present between thesupports shown in FIG. 2.

FIG. 4 is a cross-section elevation view illustrating in more detail theanchoring of a flexible fiber geogrid to an embankment support inaccordance with the present invention.

FIGS. 5 through 10 are a stepwise progression of perspective viewsshowing a method of achieving the anchoring illustrated in FIG. 4.

FIG. 11 is a cross-section elevation view illustrating a backfillearthen embankment contained between a retaining wall and a rock facewith geogrids extending therebetween, an end portion of each of thegeogrids being anchored to the rock face with apparatus in accordancewith the present invention.

FIG. 12 is a cross-section elevation view illustrating in more detailthe manner whereby the geogrids shown in FIG. 11 are anchored to therock face shown in FIG. 11.

FIG. 13 is a cross-section elevation view illustrating a backfillearthen embankment stabilized by a retaining wall and geogrids, thegeogrids being anchored to the retaining wall with apparatus inaccordance with the present invention.

FIG. 14 is a perspective view of an alternative embankment support.

FIG. 15 is a cross-section elevation view illustrating the anchoring ofa flexible fiber geogrid to the embankment support shown in FIG. 14.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate flexible fiber geogrids 5 anchored toembankment supports generally designated 11, 11 a, 12, 12 a. In FIG. 1,geogrids 5 and supports 11, 11 a serve to stabilize a vertical earthenembankment of backfill 201. In FIG. 2, geogrids 5 and supports 12, 12 aserve to stabilize a sloped earthen embankment of backfill 202.

Geogrids 5 are anchored to support 11 or 12, as the case may be, by apreferred anchoring mechanism which is generally designated 15 and whichis described below in more detail with reference to FIG. 4-10. Eachgeogrid 5 comprises a plurality of spaced elongated tension members 6extending from a forward end 7 and intersected at spaced intervals by aplurality of transverse members 8. For strength, geogrids 5 preferablyare fabricated from high density polyester material.

FIG. 3 illustrates the structure of supports 11, 11 a in more detail.Note that geogrids 5 and backfill 201 have not been included in FIG. 3so as not to obscure the structure.

Support 11 comprises a plurality of transversely spaced elongated steelwire members 20, each extending longitudinally from a hooked rearwardend or hooking member 21 (which defines an inverted U-shaped envelope)to a forward end 25, then upwardly to a hooked upper end 29. Thelowermost horizontally extending portion of wire members 20 togetherdefine a floor section of the support. Similarly, the forwardmostupwardly extending portion of wire members 20 together define a facesection of support 11 which extends upwardly at 90 degrees relative tothe floor section.

Support 11 also includes transversely extending steel wire crossbars,namely: rearward crossbar 31, intermediate crossbar 32 on the floorsection, forward crossbar 33 extending proximate forward ends 25 of wiremembers 20, and upper crossbar 34. Each of such crossbars are welded towire members 20 at their points of intersection therewith to hold wiremembers 20 in their parallel spaced relationship. As well, to provideadded strength, support 11 includes a plurality of diagonal wire braces40 each of which is hooked at its lower end to intermediate crossbar 32and at its upper end to upper crossbar 34.

The construction of support 11 a is substantially the same as that ofsupport 11. During the process of stabilizing an embankment, support 11a of course will be installed first with its geogrid 5 anchored to thesupport (in the manner described below). Then, embankment backfillsufficient to provide a base for support 11 will be added over the floorsection and rearwardly of support 11 a while leaving hooked upper ends29 of support 11 a free to engage forward crossbar 33 of support 11.

As can be seen in FIG. 3, forward crossbar 33 of support 11 is engagedby hooked upper ends 29 of support 11 a. The hooked upper ends 29 ofsupport 11 are free ends but may be used to engage the upper crossbar ofyet another similar support (not shown) positioned above the level ofsupport 11. This may be repeated for several levels or tiers of supportsand not merely the two levels depicted in FIGS. 1 and 3.

The only substantive difference between supports 11, 11 a and supports12, 12 a is that the face section of the latter extends upwardly andrearwardly at an angle of less than 90 degrees relative to the floorsection, and is thus suitable for a sloped embankment extending at thesame angle. Depending on the job at hand, it will be understood thatsupports like supports 11, 11 a, 12, 12 a may be combined in the sameproject. For example, in FIG. 3, support 11 or support 11 a could bereplaced by a support like support 12 or with a support having someother angle between its face and floor sections.

Apart from the provision of hooked upper ends 29, the construction ofsupports 11, 11 a, 12, 12 a is considered to be prior art. The advantageprovided by hooked upper ends 29 is to enable supports on successivelevels to be quickly linked in the manner shown in FIG. 3 asconstruction of a stabilized embankment proceeds and, as each newsupport is added to the structure, to enable its associated geogrid tobe anchored to the support and then tensioned while the support is heldin position by the support to which it is linked.

Each geogrid 5 is anchored to support 11, 11 a, 12, 12 a, as the casemay be, by first and second anchor rods (preferably cylindrical rods 55,60): see FIGS. 4-10 for the example of support 11. When a geogrid 5 isfully anchored to support 11 as shown in FIG. 4, each rod 55, 60 extendstransverse to the geogrid. Rod 55 is positioned rearward of rod 60outside the inverted U-shaped envelope defined by end 21 and rod 60 ispositioned forward of rod 55 within the envelope. As seen in FIG. 4,geogrid 5 extends from its forward end 7

-   -   first forwardly above rods 55 and 60 to a position above rod 60;    -   then wrappingly around rod 60 to a position below rod 60;    -   then rearwardly to a position above rod 55;    -   then wrappingly around rod 55 to a position below rod 55;    -   then forwardly to a position below rod 60;    -   then wrappingly around rod 60 to a position above rod 60;    -   then rearwardly above rod 55 and distantly away from support 11.

When longitudinal tension is applied to geogrid 5 in the direction ofarrow 100 (FIG. 4) while support 11 is held in position the geogridtightens on the rods; rod 55 is pulled by the geogrid forwardly againstthe rearward side of leg 22 of end 21; and rod 60 is pulled by thegeogrid rearwardly against the forward side of leg 22. Thus, bothforward movement of rod 55 and rearward movement of rod 60 are limitedby leg 22.

It will be note that upward movement of rod 60 is limited because it iscontained within the inverted U-shaped envelope defined by end 21. Thisis advantageous because when a worker pulls on the geogrid before rods55, 60 are drawn to the final positions shown in FIG. 4, rod 60 mayotherwise slip up and away from its anchoring position if the manualpulling force includes an upward component relative to support 11.

Reference is now made to FIGS. 5 through 10 which illustrate a stepwiseprogression of steps for anchoring geogrid 5 to support 11. As shown inFIG. 5, a forward portion of geogrid 5 is first positioned above support11 with its forward end 7 directed rearwardly. The forward portion isthen lowered in the direction of arrow 101 (FIG. 5) to the positionshown in FIG. 6 where the longitudinal tension members 6 of geogrid 5fall between hooking members 21. Although not illustrated, it may benoted that the portion of geogrid 5 not shown in FIG. 5 typically willbe rolled up in a form easy to be unrolled.

Next, anchoring rod 55 is located from a position above geogrid 5 asshown in FIG. 6 to a position atop geogrid 5 as shown in FIG. 6 (viz. inthe direction of arrow 102). Then, the forward portion of geogrid 5 asshown in FIG. 6 is folded forwardly over rod 55 to the position shown inFIG. 7 (viz. in the direction of arrow 103).

Next, as indicated in FIGS. 7 and 8, anchoring rod 60 is transverselyinserted atop the forwardly folded end portion of geogrid 5 and throughthe inverted U-shaped envelopes provided by ends 21 of support 11.

Next, as indicated in FIGS. 9 and 10 by arrows 104 and 105, both theforward portion and the remaining extension of geogrid 5 are foldedrearwardly over anchoring rod 60 to the position shown in FIG. 10.Geogrid 5 is then situated to be tensioned to the position shown in FIG.4 where it is tighened on rods 55, 60.

Other structures for supporting earthen embankments are within the scopeof the present invention. For example, FIG. 11 illustrates a case wherea backfill earthen embankment 205 lies between a retaining wall 70comprised of concrete blocks 72 and a rock face 300. Flexible fibergeogrids 80 progressively installed during the process of adding thebackfill each extend longitudinally through embankment 205 from a firstend portion 81 held and secured between adjacent blocks 72 to a secondend portion 82 secured by a pair of anchor rods 83, 84 extendingtransversely in relation to the geodgrid and anchor bolts 85. Only oneanchor bolt 85 for each geogrid 80 is visible in FIG. 11, but it will beunderstood that a number of such bolts will be used for a given geogriddepending on the width of the geogrid and the load to be carried by thebolts.

As best seen in FIG. 12, each bolt 85 comprises a shaft 86 extendingfrom one end engaged (e.g. by threading) with rock face 300 to a distalend shaped to form an eyelet 87. Rod 83 extends longitudinally througheyelet 87 and bears against the inside lower right quadrant thereof. Rod84 bears against shaft 86 and the outside lower right quadrant of eyelet87. Bolt 85 thereby limits movement of rods 83, 84. In much the samemanner as shown in FIG. 5 where the forward end of geogrid 5 is wrappedback and forth around anchor rods 55, 60, end 82 of geogrid 80 iswrapped back and forth around anchor rods 83, 84 so as to tighten on therods when geogrid 80 is pulled in longitudinal tension. (Typically, eachgeogrid 80 will be pulled and held in tension during construction whenits end portion 81 is being secured between adjacent blocks 72.

As another example, FIG. 13 illustrates a case where a backfill earthenembankment 210 is stabilized by a solid concrete retaining wallgenerally designated 90. Flexible fiber geogrids 92 progressivelyinstalled during the process of adding the backfill extend from wall 90into embankment 210. An end portion 94 of each geogrid is anchored towall 90 by means of anchor rods 83, 84 and anchor bolts 85, the latterof which are engaged with wall 90 rather than a rock face as in the caseof the embodiment shown in FIG. 11. Since the anchoring mechanism isotherwise essentially the same as the anchoring mechanism described inrelation to FIGS. 11-12, it will not be described here in any furtherdetail.

As a further example, it should be noted that embankment supports likesupport 11 can be used but without hooked rearward ends 21. Whileconsidered preferable, such hooked ends are not considered essential.More particularly, FIG. 14 shows an embankment support 111 which issimilar in construction to support 11, but with a plurality oftransversely spaced elongated steel wire members 120 instead of wiremembers 20. In the floor section of support 111, wire members 120 havestraight rearward ends rather than hooked rearward ends 21. Crossbar 31extends across the top of the straight rearward ends. FIG. 15 shows themanner whereby a geogrid 5 is anchored to the rearward end of the floorsection of support 111 by wrapping the geogrid back and forth aroundanchor rods 55, 60. Rod 55 abuts against crossbar 31 and against thetops of wire members 120. Rod 60 abuts against the bottoms of wiremembers 120. Movement of the rods 55, 60 is thereby limited.

Further Variations

A variety of modifications, changes and variations to the invention arepossible within the spirit and scope of the following claims, and willundoubtedly occur to those skilled in the art. The invention should notbe considered as restricted to the specific embodiments that have beendescribed and illustrated with reference to the drawings. In the claims,means-plus-function clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

1. A structure for stabilizing an earthen embankment, said structurecomprising: (a) an embankment support for restraining movement of atleast a part of said embankment; (b) a flexible fiber geogrid extendinglongitudinally through said embankment from a first end portion securedto said support to a second end portion; and, (c) anchor means forsecuring one of said end portions, said anchor means comprising: (i) apair of anchor rods spaced away from said embankment support andextending transversely in relation to said geogrid; and, (ii) means forlimiting movement of said anchor rods, said one of said end portionsbeing wrapped back and forth around said anchor rods so as to tightenthereon when said geogrid is pulled in longitudinal tension away fromsaid anchor means.
 2. A structure as defined in claim 1 wherein: (a)said support comprises a retaining wall; and, (b) said means forlimiting movement of said anchor rods comprises a plurality of anchorbolts, each bolt comprising a shaft extending from one end engaged withsaid wall to a distal end shaped to form an eyelet, one of said anchorrods extending through each of said eyelets.
 3. A structure as definedin claim 1, wherein: (a) said support comprises a retaining wall, (b)said earthen embankment lies between a rock face and said wall; and, (c)said means for limiting movement of said anchor rods comprises aplurality of anchor bolts, each bolt comprising a shaft extending fromone end engaged with said rock face to a distal end shaped to form aneyelet, one of said anchor rods extending through each of said eyelets.4. A structure for stabilizing an earthen embankment, said structurecomprising: (a) an embankment support for restraining movement of atleast a part of said embankment, said support comprising: (i) a floorsection extending longitudinally rearwardly from a forward end of thefloor section to a rearward end of the floor section, said rearward endof the floor section including a plurality of transversely spacedhooking members; and, (ii) a face section extending longitudinally at anangle upwardly from said forward end of the floor section to a top end;and; (b) a flexible fiber geogrid extending longitudinally rearwardlyfrom said floor section and anchored thereto by first and second anchorrods engaging said hooking members and extending transverse to saidgeogrid, said first anchor rod being positioned rearward of said secondanchor rod; movement of said anchor rods relative to said support beinglimited by said hooking members when said geogrid is pulled in rearwardlongitudinal tension.
 5. A structure as defined in claim 4, wherein: (a)each of said hooking members defines an inverted U-shaped envelope, saidsecond anchor rod extending through the envelope of each of said hookingmembers, said first anchor rod extending outside the envelope of each ofsaid hooking members; and, (b) said geogrid extends from a forward endof said geogrid: (i) first forwardly above said first anchor rod to aposition above said second anchor rod; (ii) then wrapping around saidsecond anchor rod to a position below said second anchor rod; (iii) thenrearwardly to a position above said first anchor rod; (iv) then wrappingaround said first anchor rod to a position below said first anchor rod;(v) then forwardly to a position below said second anchor rod; (vi) thenwrapping around said second anchor rod to a position above said secondanchor rod; (vii) then rearwardly above said first anchor rod and awayfrom said support.
 6. A structure as defined in claim 4, wherein: (a)said support includes a transversely extending crossbar positionedproximate to said forward end of said floor section; and, (b) said topend of said face section includes a plurality of transversely spacedhooks for engaging a like crossbar of a like support.
 7. A structure asdefined in claim 6, wherein: (a) each of said hooking members defines aninverted U-shaped hooking envelope, said second anchor rod extendingthrough the hooking envelope of each of said hooking members, said firstanchor rod extending outside the envelope of each of said hookingmembers; and, (b) said geogrid extends from a forward end of saidgeogrid: (i) first forwardly above said first anchor rod to a positionabove said second anchor rod; (ii) then wrapping around said secondanchor rod to a position below said second anchor rod; (iii) thenrearwardly to a position above said first anchor rod; (iv) then wrappingaround said first anchor rod to a position below said first anchor rod;(v) then forwardly to a position below said second anchor rod; (vi) thenwrapping around said second anchor rod to a position above said secondanchor rod; (vii) then rearwardly above said first anchor rod and awayfrom said support.
 8. A structure for stabilizing an earthen embankment,said structure comprising: (a) an embankment support for restrainingmovement of at least a part of said embankment, said support comprising:(i) a plurality of parallel spaced elongated wire members, eachextending longitudinally from a hooked rearward end to a forward endthen upwardly to an upper end; said wire members together defining afloor section of said support and a face section of said support; and,(ii) a plurality of transversely extending crossbars secured to saidwire members for holding said wire members in said parallel spacedrelationship; and; (b) a flexible fiber geogrid extending longitudinallyrearwardly from said floor section and anchored thereto by first andsecond anchor rods engaging said hooked rearward ends and extendingtransverse to said geogrid, said first anchor rod being positionedrearward of said second anchor rod; movement of said anchor rodsrelative to said support being limited by said hooked rearward ends whensaid geogrid is pulled in rearward longitudinal tension.
 9. A structureas defined in claim 8, wherein: (a) each of said hooked rearward endsdefines an inverted U-shaped envelope, said second anchor rod extendingthrough the envelope of each of said hooked rearward ends, said firstanchor rod extending outside the envelope of each of said hookedrearward ends; and, (b) said geogrid extends from a forward end of saidgeogrid: (i) first forwardly above said first anchor rod to a positionabove said second anchor rod; (ii) then wrapping around said secondanchor rod to a position below said second anchor rod; (iii) thenrearwardly to a position above said first anchor rod; (iv) then wrappingaround said first anchor rod to a position below said first anchor rod;(v) then forwardly to a position below said second anchor rod; (vi) thenwrapping around said second anchor rod to a position above said secondanchor rod; (vii) then rearwardly above said first anchor rod and awayfrom said support.
 10. A structure as defined in claim 8, wherein: (a)one of said crossbars is a forward crossbar extending proximate to saidforward ends of said wire members; and, (b) said upper end of each ofsaid wire members is hooked for engaging a like forward crossbar of alike support.
 11. A structure as defined in claim 10, wherein: (a) eachof said hooked rearward ends defines an inverted U-shaped envelope, saidsecond anchor rod extending through the envelope of each of said hookedrearward ends, said first anchor rod extending outside the envelope ofeach of said hooked rearward ends; and, (b) said geogrid extends from aforward end of said geogrid: (i) first forwardly above said first anchorrod to a position above said second anchor rod; (ii) then wrappingaround said second anchor rod to a position below said second anchorrod; (iii) then rearwardly to a position above said first anchor rod;(iv) then wrapping around said first anchor rod to a position below saidfirst anchor rod; (v) then forwardly to a position below said secondanchor rod; (vi) then wrapping around said second anchor rod to aposition above said second anchor rod; (vii) then rearwardly above saidfirst anchor rod and away from said support.
 12. A method of anchoring aflexible fiber geogrid to a support for stabilizing an earthenembankment, said support comprising an upwardly extending face sectionand a floor section extending longitudinally rearwardly from said facesection, said floor section comprising a plurality of transverselyspaced hooking members, said geogrid comprising longitudinally extendingwebs sized and spaced to fit between said hooking members; said methodcomprising: (a) positioning a forward end portion of said geogrid atopsaid floor section such that said longitudinally extending webs extendbetween said hooking members; (b) then positioning a first anchor rodatop said end portion rearward of said hooking members; (c) then foldingsaid end portion forwardly over said first anchor rod; (d) thenpositioning a second anchor rod atop said end portion forward of saidfirst anchor rod; (e) then folding said end portion and said geogridrearwardly over said second anchor rod.
 13. A method as defined in claim12, wherein said support comprises a plurality of parallel spacedelongated wire members, each of said wire members extendinglongitudinally from a rearward end to a forward end then upwardly to anupper end; said wire members together defining said floor section ofsaid support and said face section of said support; each of said wiremembers including one of said hooking members at its rearward end.
 14. Amethod as defined in claim 12, wherein each of said hooking membersdefines an inverted U-shaped envelope, and wherein said methodcomprises: (a) positioning said first anchor rod rearward of saidenvelope; and, (b) inserting said second anchor rod progressivelythrough the envelope of each of said hooking members to a positionextending through the envelope of all of said hooking members.
 15. Amethod as defined in claim 14, wherein said support comprises aplurality of parallel spaced elongated wire members, each of said wiremembers extending longitudinally from a rearward end to a forward endthen upwardly to an upper end; said wire members together defining saidfloor section of said support and said face section of said support;each of said wire members including one of said hooking members at itsrearward end.